Geochemical Characteristics Zeolite Clay From The Central Indian Ocean Basin And The Implications For Enrichement Process Of REY

REY-rich deep-sea sediment used to be zeolite clay in Pacific. It is worth thinking about whether the phillipsite-rich Central Indian Ocean Basin(CIOB) is also rich in such clay. In this paper, we will select a REY-rich deep-sea sediment core GC02 that collected from CIOB as the main object of study as well compare with a siliceous clay core BC02 and results from the previous workers. Based on the the measurements of major, trace, rare earth elements as well as the observations on minerals, we have a discussion on the geochemistry, carries, sources and accumulation factors of the rare earth elements. Points are as follows.1)The EREY in GC02 varies from 685.51 to 1392.24ppm with 1072.17ppm in average that 6.33 times more than upper crust. While in BC02, theEREY varies from 214.14 to 279.16ppm with 265.41ppm in average.2)Generally, the core GC02 consists of zeolite bearing debris and clays while biogenic siliceous sediment dominates the BC02, indicating that the REY is more hosted in zeolite caly zones than the siliceous clay zones, in accord with the Pacific.3)The elements such as Fe, Mn, Zn, Cu, As, Mo, V and U show a maximum peak in the layer 128-130cm in GC02, and Ca as well as Sr show a maximum peak in the layer 134-146cm, perhaps indicating that the events of fast-settling of hydrothermal or calcareous matters dilute the ∑REY.4)The most different major element between the two cores is P that the core GC02 is 7.15 times more than BC02, moreover, P has a good positive relationship with ∑REY, indicating that fish teeth/debris(consist of fluorapatite) may be the main carrier of the rare earth elements.5)A good positive relationship between EREY and Co is observed, indicating that the rare earth elements are likely to hydrogenous. However, considering the MREE-rich type PAAS normalized pattern, the discrimination by Y/Ho-∑REE plot, and the good positive relationship between MREE* and K, the rare earth elements may be also attributed from terrigenous materials.6)There may exists a process that rare earth elements redistributed from debris, Fe/Mn oxides to apatites via pore water that affected the normalized patterns of the REY-rich deep-sea mud.